This invention relates to a semiconductor integrated circuit having a ferroelectric (high dielectric) capacitor and a manufacturing method of the integrated circuit. In particular, the present invention relates to technique which is effective when adapted to a process for forming a conductive material, which constitutes a lower electrode of the capacitor, at a high aspect ratio or with high anisotropy.
Described in Japanese Patent Application Laid-Open No. Hei 10-98162 (Yunogami, et al.) is technique for patterning a thin film such as Pt film by dry etching through a resist mask with a view to forming a minute pattern at high dimensional accuracy without leaving a low vapor-pressure reaction product on the side surface of the pattern, wherein the dry etching is carried out using, as a mask, a photo resist of a predetermined pattern having, at at least the lower half portion thereof, a perpendicular side surface and a forward taper or roundness at the outer periphery of the head portion so as to form, on the side surface of the thin-film pattern, a forward taper reaching the lower end of the thin film.
Described in Japanese Patent Application Laid-Open No. Hei 8-153707 (Tokashiki) is technique of selectively dry etching an electrode containing ruthenium or ruthenium oxide and then treating the surface of the electrode with oxygen, ozone, water vapor or nitrogen oxide gas, with a view to removing the contamination of carbon or halogen which has appeared, during the formation of a minute pattern of platinum or conductive oxide, on its surface and at the same time, making the surface condition of the electrode similar or almost similar to that upon formation of the electrode material.
Disclosed in Japanese Patent Application Laid-Open No. Hei 9-266200 (Nakagawa, et al.) with a view to facilitating minute processing of a ferroelectric substance or platinum is the following technique. Described specifically, a laminate film of a lower platinum film, a ferroelectric film and an upper platinum film is formed over a device insulating film on a semiconductor substrate, followed by the formation of a titanium film having a film thickness not greater than one-tenth of the laminate film. After patterning the titanium film through a photo resist film, the laminate film is etched with the patterned titanium film by using a gas mixture of oxygen and chlorine having an oxygen concentration of 40%. Then the titanium film is removed by etching with a chlorine gas.